本文实例为大家分享了PyQt5实现画布小程序的具体代码，供大家参考，具体内容如下

实现的效果图如下：

该实例中，涉及到的知识点有：

1.PyQt5 的常用的布局方式，这里使用到了QVBoxLayout，QHBoxLayout，如何灵活运用这些布局；

2.常用组件的使用方法，这里使用到了QPushButton, QLabel, QPixmap；

3.使用QPainter进行绘制；

4.事件与槽；

主要代码如下：

import randomimport sys from PyQt5.QtCore import QSizefrom PyQt5.QtGui import QPixmap, QPainter, QColorfrom PyQt5.QtWidgets import QMainWindow, QLabel, QApplication, QPushButton, QWidget, QVBoxLayout, QHBoxLayout SPRAY_PARTICLES = 100SPRAY_DIAMMETER = 10 COLORS = [ '#000000', '#141923', '#414168', '#3a7fa7', '#35e3e3', '#8fd970', '#5ebb49', '#458352', '#dcd37b', '#fffee5', '#ffd035', '#cc9245', '#a15c3e', '#a42f3b', '#f45b7a', '#c24998', '#81588d', '#bcb0c2', '#ffffff',] class QPlatteButton(QPushButton): def __init__(self, color): super().__init__() self.setFixedSize(QSize(24, 24)) self.color = color self.setStyleSheet("background-color: %s" % self.color) class Canvas(QLabel): def __init__(self): super().__init__() canvas = QPixmap(1200, 800) canvas.fill(QColor('white')) self.setPixmap(canvas) self.last_x, self.last_y = None, None self.pen_color = QColor('#000') def set_pen_color(self, c): self.pen_color = QColor(c) def mouseReleaseEvent(self, *args, **kwargs): """ 松开鼠标事件 """ self.last_x, self.last_y = None, None def mouseMoveEvent(self, e): """ 移动鼠标事件 """ if self.last_x is None: self.last_x = e.x() self.last_y = e.y() return painter = QPainter(self.pixmap()) pen = painter.pen() pen.setWidth(4) pen.setColor(self.pen_color) painter.setPen(pen) painter.drawLine(self.last_x, self.last_y, e.x(), e.y()) painter.end() self.update() # update the origin for next time self.last_x = e.x() self.last_y = e.y() # def mouseMoveEvent(self, e): # painter = QPainter(self.pixmap()) # p = painter.pen() # p.setWidth(1) # p.setColor(self.pen_color) # painter.setPen(p) # # for n in range(SPRAY_PARTICLES): # xo = random.gauss(0, SPRAY_DIAMMETER) # yo = random.gauss(0, SPRAY_DIAMMETER) # painter.drawPoint(e.x() + xo, e.y() + yo) # # self.update() class MainWindow(QMainWindow): def __init__(self): super().__init__() self.setWindowTitle("画板小程序") self.canvas = Canvas() widget = QWidget() vlayout = QVBoxLayout() widget.setLayout(vlayout) vlayout.addWidget(self.canvas) palette = QHBoxLayout() vlayout.addLayout(palette) self.add_palette_buttons(palette) self.setCentralWidget(widget) def add_palette_buttons(self, layout): """ 在水平布局中放入一行调色板 """ for c in COLORS: b = QPlatteButton(c) b.pressed.connect(lambda c=c: self.canvas.set_pen_color(c)) layout.addWidget(b) if __name__ == '__main__': app = QApplication(sys.argv) window = MainWindow() window.move(120, 120) window.show() app.exec_()

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。